US Patent 7891785 Liquid jet head and a liquid jet apparatus

An upper surface of a piezoelectric layer in an area opposed to a pressure generating chamber and a side surface of the piezoelectric layer in an arrangement direction of the piezoelectric elements are covered with an upper electrode. In addition, on one end in a longitudinal direction of the piezoelectric element, the piezoelectric layer extends up to an adhesive area of a flow passage forming substrate to which a circumferential portion of a piezoelectric element preserver of a joining substrate is adhered, and the lower electrode extends up to the outside of an end portion of the piezoelectric layer to form a terminal section in an end portion of the lower electrode.